U.S. Pat. No. 4,714,433 discloses assembling together two electrical connector elements each having a locking arm. One of the locking arms is made integrally with the body of the corresponding electrical connector element, said arm being elastically deformable. The other locking arm is constituted by a separate piece pivotally mounted on the body of the other connector element. The arms are suitable for co-operating by snap-fastening to lock the assembly together.
U.S. Pat. No. 4,941,839 also discloses a locking device for an electrical connector including a piece that is pivotally mounted on a housing and elastically biased by means of a spring.
The connectors described in the two above-mentioned patents are of relatively complex structure.
In addition, U.S. Pat. No. 5,487,678 describes a locking device for an electrical connector, one of the connector elements having an elastically deformable tab suitable for co-operating with a shape on the other connector element. Unlocking is performed by exerting an upwardly-directed force on the resilient tab. That device does not enable accidental unlocking to be prevented.